"volume clamp"

Intraoperative hypotension (IOH) is common during major surgery and is associated with a poor postoperative outcome. Hypotension Prediction Index (HPI) is an algorithm derived from machine learning that uses the arterial waveform to predict IOH. The aim of this study was to assess the diagnostic ability of HPI working with non-invasive ClearSight system in predicting impending hypotension in patients undergoing major gynaecologic oncologic surgery (GOS). In this retrospective analysis hemodynamic data were downloaded from an Edwards Lifesciences HemoSphere platform and analysed...

Introduction: Cardiovascular system is the vitally important system in the dynamical adaptation process of the newborns to the extrauterine environment. To reliably detect immaturity in the given organ system, it is crucial to study the development of the organ functions in relation to maturation process. Objectives: The objective was to determine the changes in the spontaneous short-term blood pressure variability (BPV) and baroreflex sensitivity (BRS) reflecting various aspects of cardiovascular control during the process of maturation in preterm babies and to separate effects of gestational age and postnatal age...

Objective: In this study we compared noninvasive arterial pressure measurement using ClearSight™ vascular-unloading-technique (Edwards Lifesciences Corp, Irvine, CA) with invasive arterial pressure measurement during induction of anesthesia undergoing mayor cardiac surgery. Design: Prospective, monocentric. Setting: University hospital. Participants: 54 patients undergoing mayor cardiac surgery. Interventions: During induction all patients were simultaneously monitored with invasive (reference method) and noninvasive arterial pressure measurement (test-method) over a mean time period of 27 minutes...

The finger-cuff system CNAP (CNSystems Medizintechnik, Graz, Austria) allows non-invasive automated measurement of pulse pressure variation (PPVCNAP ). We sought to validate the PPVCNAP -algorithm and investigate the agreement between PPVCNAP and arterial catheter-derived manually calculated pulse pressure variation (PPVINV ). This was a prospective method comparison study in patients having neurosurgery. PPVINV was the reference method. We applied the PPVCNAP -algorithm to arterial catheter-derived blood pressure waveforms (PPVINV-CNAP ) and to CNAP finger-cuff-derived blood pressure waveforms (PPVCNAP )...

BACKGROUND AND AIMS: Elderly patients aged ≥65 years represent a growing population in the perioperative field, particularly orthopedic and vascular surgery. The higher degree of age-related or comorbid-dependent vascular alterations renders these patients at risk for hemodynamic complications and likely denote a possible limitation for modern, non-invasive arterial pressure monitoring devices. The aim was to compare vascular unloading technique-derived to invasive measurements of systolic (SAP), diastolic (DAP), and mean arterial pressure (MAP) in elderly perioperative patients...

Despite blood pressure being one the leading modifiable risk factors for cardiovascular disease and death, it is severely under-monitored. For this challenge we propose a finger artery non-invasive tono-oscillometric monitor (FANTOM) which is an automated low-cost instrument for measuring blood pressure and hemodynamic parameters from the fingertip. The sensing technology is highly scalable and could be integrated to a pulse oximeter probe for increased patient comfort. A tonometric cuff-less mechatronic system is used to apply pressure on the fingertip for (i) measuring oscillometric blood pressure, (ii) recording arterial waveform and for (iii) constructing central blood pressure (CBP) waveform...

Baroreflex response consists of cardiac chronotropic (effect on heart rate), cardiac inotropic (on contractility), venous (on venous return) and vascular (on vascular resistance) arms. Because of its measurement simplicity, cardiac chronotropic arm is most often analysed. The aim was to introduce a method to assess vascular baroreflex arm, and to characterize its changes during stress. We evaluated the effect of orthostasis and mental arithmetics (MA) in 39 (22 female, median age: 18.7 yrs.) and 36 (21 female, 19...

Arterial blood pressure monitoring is a major part of the decision-making process for every anesthetic. It is important to recognize the advantages, disadvantages, and limitations of available measurement modalities as well as have some understanding of the engineering principles on which these measurements are based. Oscillometry is by far the most common modality used but is limited by its intermittent nature and inaccuracy during hypotension and hypertension. Arterial catheterization is the gold standard for measuring blood pressure but is an invasive procedure that is expensive and not without risk of harm to the patient...

PURPOSE: Respiratory variations in pulse pressure (dPP) and photoplethysmographic waveform amplitude (dPOP) are used for evaluation of volume status in mechanically ventilated patients. Amplification of intrathoracic pressure changes may enable their use also during spontaneous breathing. We investigated the association between the degree of hypovolemia and dPP and dPOP at different levels of two commonly applied clinical interventions; positive expiratory pressure (PEP) and continuous positive airway pressure (CPAP)...

AIM: Motivated by the paradoxical and differing results of the early atherosclerosis related indices - Cardio-Ankle Vascular Index (CAVI) reflecting arterial stiffness and Reactive Hyperemia Index (RHI) evaluating endothelium dependent flow-induced vasodilation - in obesity, we aimed to assess CAVI and RHI in obese adolescents and young adults in the context of differences in systemic vascular resistance (SVR). METHODS: We examined 29 obese (14f, 15.4 [12.3-18.5] y; BMI: 33...

BACKGROUND: Continuous beat-to-beat blood pressure monitoring permits the rapid detection of blood pressure fluctuations for cardiovascular reflex testing and clinical haemodynamic monitoring. In adults, this can be achieved noninvasively with high accuracy, using finger blood pressure monitoring with volume clamp photoplethysmography. However, data are lacking on the validity of finger blood pressure monitoring in children compared to the gold standard - invasive intra-arterial blood pressure monitoring...

During interventional and structural cardiology procedures, such as mitral valve (MitraClip, BMV), aortic valve (TAVR, BAV), tricuspid valve (MitraClip), left atrial appendage (Watchman, Lariat), atrial septum (ASD/PFO closure), and coronary artery intervention (high-risk PCI), among others, patients are at a high risk of hemodynamic instability and require continuous monitoring. This is conventionally achieved through arterial catheterization and transpulmonary thermodilution. However, such invasive techniques are time-consuming and have been associated with steep learning curves, vascular complications, and increased risk of infection...

BACKGROUND: Continuous noninvasive blood pressure (CNBP) measurement using the volume-clamp method is a less invasive alternative compared with invasive intra-arterial monitoring for awake patients during carotid endarterectomy (CEA) under regional anaesthesia. OBJECTIVE: We investigated the agreement of blood pressure (BP) recorded with invasive and CNBP methods during awake CEA. DESIGN: A prospective observational study for assessing agreement with Bland-Altman plots, agreement-tolerability indices (ATI), concordance and interchangeability...

Cardiovascular diseases are the leading cause of death whereas nocturnal ambulatory blood pressure (BP) is the most potent predictor for cardiovascular risk. Volume clamp and Pulse Transit Time (PTT) are common methods for continuous non-invasive BP measurement, but have drawbacks during unsupervised ambulatory use and undisturbed sleep. The Pulse Propagation Time (PPT), defined as time between Pulse Wave Systolic Peak and Diastolic Peak, provides valid information about the pressure pulse waveform. However, the literature has not investigated the use of PPT for nocturnal BP variation determination and if such variation is affected by BP or heart rate (i...

BACKGROUND: The Continuous Non-Invasive measurement of arterial Blood Pressure [CNIBP] is possible via the method of arterial tonometry and the arterial volume clamp methods. Arterial tonometry successfully measures continuous arterial pressure but requires large vessel deformation and a highly miniaturized pressure sensor to obtain a direct calibration of pressure. A properly designed tonometer is capable of achieving pressure accuracy of less than 5% error at the radial artery. The volume clamp method achieves comparable errors but is generally restricted to the very peripheral arteries...

This work presents non-invasive evaluation of the arterial blood pressure (ABP) waveform during the Valsalva maneuver. Ultrasound scanning is conducted to acquire blood flow and arterial distension signals. Motion-tolerant ultrasound measurement schemes are employed by using two wide rectangular transducers. Pulse pressure (PP) estimated at the common carotid artery is compared to that of a finger waveform measured by a volume clamping device. The changes of PP are correlated between the two measurements. A more depressed dicrotic notch during the Valsalva strain is observed, and beat-to-beat variations of PP and a pulse rate caused by respiration and baroreflex is observed during the control...

An ideal non-invasive monitoring system should provide accurate and reproducible measurements of clinically relevant variables that enables clinicians to guide therapy accordingly. The monitor should be rapid, easy to use, readily available at the bedside, operator-independent, cost-effective and should have a minimal risk and side effect profile for patients. An example is the introduction of pulse oximetry, which has become established for non-invasive monitoring of oxygenation worldwide. A corresponding non-invasive monitoring of hemodynamics and perfusion could optimize the anesthesiological treatment to the needs in individual cases...

BACKGROUND: Echocardiography is usually performed with the subject/patient lying in the left lateral position (LLP), because the acoustic window is better in this than in the supine position (SP). The aim was to investigate cardiac responses to rotational changes of position in the transversal plane, from SP to LLP while horizontal, and from leaning on the back (HUT-LB) to leaning on the left side (HUT-LL) while tilted 60° head-up from the horizontal. METHODS: Healthy men (n = 12) underwent 10-min HUT provocations...

High blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertension awareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertension management, but existing devices require an inflatable cuff and are not compatible with such anytime, anywhere measurement of BP. We extended the oscillometric principle, which is used by most automatic cuff devices, to develop a cuff-less BP monitoring device using a smartphone. As the user presses her/his finger against the smartphone, the external pressure of the underlying artery is steadily increased while the phone measures the applied pressure and resulting variable-amplitude blood volume oscillations...

Volume-clamp technology (e.g. Finometer) has become a popular method of collecting continuous, non-invasive, hemodynamic information during hemodialysis. There is minimal data validating the technique in this patient group. A gold standard cardiac output measurement can be obtained using ultrasound dilution in patients with arterio-venous fistulae. Continuous cardiac output was measured in 124 hemodialysis sessions in 27 patients using a volume-clamp device (Finometer PRO). Ultrasound dilution measurement was first taken at baseline (Transonic HD03), then used to calibrate the Finometer...